Field of the Invention
The present disclosure relates to light-emitting elements.
Description of the Related Art
In general, a light-emitting element (light-emitting diode: LED) including a semiconductor, such as a nitride semiconductor, is usually configured by stacking an n-type semiconductor layer, an active layer, and a p-type semiconductor layer over a sapphire substrate in this order. To improve light extraction efficiency of the light-emitting element, some techniques are conventionally proposed that involve previously forming elongated concave portions or a composite structure of elongated concave and convex portions on a sapphire substrate (see JP 2008-53385 A, JP 2008-91942 A, and JP 2012-114204 A).